To find which package a file is from just pass it the path to the file in question, whether it's a config file or binary, you'll find your answer (assuming it does belong to a package of course).
Just use dpkg -S /path/to/yourfile
eg.
dpkg -S /usr/bin/xed
xed: /usr/bin/xed
dpkg -S /etc/pam.conf
libpam-runtime: /etc/pam.conf
debian, mint, ubuntu, linuxto, config, binary, ll, dpkg, yourfile, linux, eg, usr, bin, xed, etc, pam, conf, libpam, runtime,